Coastal and marine wetlands in Gulf St. Vincent, South Australia: understanding their loss and degradation

Abstract

Despite the vastness of South Australia's coastline, approximately 95% of the state's population of 1.4 million is on the Adelaide metropolitan coast of Gulf St. Vincent. The concentration of human activity around this shallow, sheltered gulf ecosystem has led to conflict and competition over the use of marine and coastal resources. The gulf supports extensive areas of ecologically significant subtidal and tidal coastal wetlands, comprising seagrass meadows, mangroves and saltmarshes, with nine wetlands having recognized national importance. The wetlands support economic activities such as commercial and recreational fishing, tourism and aquaculture, and to a lesser extent, mineral and petroleum exploration and shipping. These environments and activities are threatened by the effects of land-based urbanization, coastal development, stormwater runoff effluent and industrial discharges, and the resultant decline in water quality and food-chain contamination. Marine activities can also have adverse effects (i.e., dredging, sea-dumping, overfishing, fishing methods, oil spills, antifoulants, ballast water introductions), including the developing aquaculture industry. The continued loss and degradation of marine and coastal wetlands in the gulf is exacerbated by inadequate protection measures, lack of integrated management structures and policies, and conflict between competing user groups. Strong policies and integrated decision making based on sound information is required for the equitable and sustainable use of these wetlands. Gulf-level management of multiple-uses would limit the cumulative impacts of human use and coastal development. There is a particular need to protect areas with high conservation value and for future research and marine conservation to focus on the coastal nearshore ecosystem. High priorities are coastal and biodiversity inventories, understanding of ecological processes, linkages between coastal and offshore habitats, and coastal spatial mapping and information systems.